A new epidemic focus of zoonotic cutaneous leishmaniasis in central Iran

Reports from the health center of Yazd province of increasing cutaneous leishmaniasis (CL) cases led us to carry out an epidemiological study using standard techniques in Ardakan County, central Iran, during 2001.

Data was collected on the prevalence of scars and ulcers over a period of 14 months among 621 households in three villages around Ardakan County. Smears were prepared by scraping the edges of the ulcers. We collected the same data on all school children aged 7 to 11 years old in the area. To determine the reservoir host of the disease, rodents and dogs were caught and examined. Sandflies were collected biweekly from indoor and outdoor locations in the study area, and then identified. Parasites isolated from human and rodents were characterized by RAPD-PCR technique.

The prevalence of scars and ulcers were 30.4% and 24.6%, respectively, in 3024 individuals in the three villages. Individuals 10 to 14 years of age were the most highly infected age group, with a rate of 28.4%. Males and females were equally infected. Examination of 892 students in primary schools showed a rate of 22.9% for scars and 23.7% for ulcers. Meriones libycus (42.2%) and Rhombomys opimus (57.8%) were present around the villages. Both were infected with Leishmania. Three of 19 M. libycus (15.7%) and 3 out of 26 R. opimus (11.5%) had positive results. The active season of sandflies was late April to late November. Phlebotomus papatasi and Sergentomyia sintoni were the dominant species indoors and outdoors. Natural leptomonad infection was found in P. caucasicus and S. sintoni from gerbil and Jird burrows.

Based on this survey, there is an epidemic of zoonotic CL in the area, with Leishmania major as the agent, M. libycus and R. opimus as the reservoir hosts, and most probably Phlebotomus papatasi as the vector because about 77% of indoor sandflies were of this species.